Bradley Wiggins is good with throw-away comments but the one he produced at the stage start in Pau during the 2007 Tour was surprising even by his standards. "You know," he mused. "I really didn't realise I was that good." From an Olympic champion, world champion and multiple medallist, it was a jaw dropper. But it now makes sense in a way: in his early years, pre-Beijing, Wiggins had little to refer to in order to make a serious assault on the Tour de France.

It also adds to the feeling that here is a person who would like to be ordinary but who has achieved something truly extraordinary, almost in spite of himself. Famously Wiggins likes to hide away. His mobile phone is most often switched off and calls are rarely returned. But the ability to retreat from the world is part of what enables him to achieve the total focus on what he does, which in turn explains the six Olympic medals, three of them gold, the world titles and, finally, the Tour de France.

There were hints, even in those early Tours, that Wiggins might eventually achieve greatness but they make sense only in hindsight. He finished fifth in the stage 13 time trial around Albi in 2007 and in the same year he rode over the hors categorie Col de l'Iseran in the Alps in the front group, without really meaning to. For a rider who had yet to lose weight for a serious assault on the road, that pointed to ability. And there was another little hint that he could handle the workload of the Tour when he wrote in the Observer that he was recovering well in his first Tour, waking up each morning hungry and ready for the day ahead.

If he had ambitions, it is not surprising that he did not make them public. That is not his way. "He is a very private person, he protects that side of his character, as he doesn't want to show chinks in the armour," one of his former coaches said. "I am good at ignoring people and shutting things out and burying my head in the sand," Wiggins said. "And it works for cycling. It probably doesn't work for other parts of your life."

It was Steve Peters, the British Cycling psychiatrist, who compared Wiggins to a tiger. Peters likes to compare most athletes to dogs but tigers, he says, are a case apart: they retire to their lair and make contact when it is needed. If you approach them, occasionally they bite but you should expect that. You are dealing with a tiger after all.

The sense is of a vulnerable man, who needs to put up barriers to protect himself from the world, explained in part by his complicated family background: on Saturday he spoke of "my father leaving us when I was a kid, growing up with my mum in the flat my grandfather brought us up in. He was my role model. He died during the 2010 Tour de France, so when I came home from the Tour I had to go to the funeral."

But on occasion, such as around the dinner table with his team-mates, or when his hair is down, Wiggins is transformed. Tales of his ability as a mimic are legendary and his former Great Britain team manager John Herety recalls one occasion when he entered a hotel room to find his youthful charge and another rider, Steve Cummings, filming a mock interview in which Cummings fired questions at Wiggins, who was lying in the bed getting fatter – thanks to the use of blankets and pillows – each time the "camera" panned back to the questioner. His former team-mate Rob Hayles has spoken of watching Wiggins belting out Jumping Jack Flash at David Millar's wedding and recalled the bar staff at another rider's wedding being so inebriated with mirth at his antics that they stopped taking payment for drinks.

If there is one thing that sets Wiggins apart from many of his peers, it is not his love of mod culture or his sideburns but his sense of perspective, which explains in part his desire to keep himself to himself. "The thing I kept reminding myself about in the last three weeks is that it's only sport. It's not life and death. There is that craziness: you finish a stage and it's like a mass murderer going into court, police pushing people and stuff. That's not reality. I've got other things in life that mean more to me; I'd give this up tomorrow. Sport is something to aspire to that keeps you going every day, something to give you routine. I'll go home and I'll have to clear up dog muck and horse muck." He is a man who craves ordinariness, with an extraordinary season behind him already and perhaps more to come.